Device for changing pitch of stack

ABSTRACT

The purpose of the invention is to efficiently perform the work of changing stacked objects, which are stacked in one container with one pitch, to another pitch and storing same in the stacked form in another container. Multiple workpieces ( 51 ) are juxtaposed in a stacked form with a prescribed pitch and attachment pads ( 25 ) for attaching the workpieces are provided on base plates ( 3 ). The pitch between the base plates can be varied by rotating variable spacers ( 17 ), which work in concert with a drive shaft ( 31 ). An airtight communicating channel ( 28 ), which communicates with the attachment pads, is formed within a group of base plates. The communicating channel ( 28 ) is formed by the consecutive installation of an expandable elastic packing ( 15 ) between the through holes of adjacent base plates. The elastic packing and the variable spacers move in concert with the base plates. The base plates are provided with springs ( 9 ) for releasing the fixing of an inter-base plate pitch. Areas of differing thickness are formed on the circumferential surface of the variable spaces ( 17 ).

FIELD OF ART

The present invention relates to a device for changing a pitch of a plurality of thin works, which are juxtaposed in a stacked form with a predetermined pitch.

BACKGROUND ART

When, for example, thin objects such as solar panels, which are called cells (hereinlater referred to as “works”) are to be transferred from one container to another container, they may have different pitches between the juxtaposed in a stacked form, due to some reasons in the production process.

In such cases, the works have been manually transferred one by one to the container having a different pitch. However, this measure is extremely inefficient. In addition, in case of a thin work such as a solar panel, the work would easily be damaged if an unexpected external force should be applied thereto in an oblique direction.

When a robot is used to achieve the above-described transfer, it is possible to prevent application of such an unexpected force to the work. However, this will also require that the works should be transferred one by one and, therefore, cannot improve the efficiency.

The present invention is a device for changing only a pitch between the works, while remaining the stacked form of the works. In connection with such device, we have tried to find technology by inputting the keywords of “pitch”, “suction (adhesion, absorption)” and “variable (changeable)” in International Patent Classification “B65H 3/00”, no relevant information has been found. The following is reference information.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP H05-253877

SUMMARY OF INVENTION Problems to be Solved by the Invention

An object of the present invention is to solve the above-described drawback and efficiently achieve the process of transferring a stack stored in a stacked form in one container with one pitch (a small pitch, for example) to another container in which the objects are stored and stacked with another pitch (a large pitch, for example), including pitch changing operation.

Another object is to achieve the above-described transfer operation surely, stably and smoothly.

Still another object is to detect whether or not the work to be transferred has any defects.

Means for Solving the Problems

To achieve the above-described objects, a device for changing a pitch of a plurality of thin works juxtaposed in a stacked form with a predetermined pitch between adjacent ones, which is characterized in that; it comprises a movable holder unit and a drive unit for driving the movable holder unit. The movable holder unit comprises a plurality of base plates juxtaposed in a stacked form with a predetermined pitch, each of said base plates includes operating member(s) that support the work, the operating member(s) being driven by drive power supplied from communicating channel(s) to hold the work individually. Each of said base plates includes rotatable variable spacer(s) interlocking with a drive shaft of the drive unit, and the pitch between the base plates becomes variable by rotation of the variable spacer(s). When the work is held by each of said base plate, the airtight, expandable communicating channel(s) is formed between the base plates in communication with the operating member.

It is further characterized in that, in the stack pitch changing device according to claim 1, the communicating channel is formed by expandable elastic packings mounted in series between through holes of the adjacent base plates.

It is further characterized in that, in the stack pitch changing device according to claim 2, each of said elastic packing is moved along with each base plate.

It is further characterized in that, in the stack pitch changing device according to claim 1, each of said variable spacer is moved along with each base plate.

It is further characterized in that, in the stack pitch changing device according to claim 1, each of said base plate is provided with spring(s) for releasing the fixed pitch between the base plates.

It is further characterized in that, in the stack pitch changing device according to claim 2, the elastic packing is formed like bellows.

It is further characterized in that, in the stack pitch changing device according to claim 1, the variable spacer has different parts having different thickness formed on its circumferential surface, and the pitch between the base plates may be changed by rotating the variable spacer so that the base plate becomes in contact with another part of different thickness.

It is further characterized in that, in the stack pitch changing device according to claim 5, the spring at a side of a stationary base plate has a spring force for restoring the contracted base plate, which is greater than a spring force of the spring at a side of a movable base plate.

It is further characterized in that, in the stack pitch changing device according to claim 8, the spring forces are made smaller stepwise toward the movable base plate for every predetermined number of the base plate.

It is further characterized in that, in the stack pitch changing device according to claim 8, the spring forces are made smaller linearly toward the movable base plate.

It is further characterized in that, in the stack pitch changing device according to claim 5, the spring comprises a single spring.

It is further characterized in that, in the stack pitch changing device according to claim 5, the springs comprise a stack of plural springs.

It is further characterized in that, in the stack pitch changing device according to claim 1, there is provided a detection unit for detecting the work condition such as crack or damage when absorbing the work.

It is further characterized in that, in the stack pitch changing device according to claim 13, the detection unit comprises an opening/closing valve mounted at an entrance of the communicating channel for opening and closing the communicating channel, an orifice mounted to the opening/closing valve in communication with a vacuum pressure detection path, and a sensor connected to the vacuum pressure detection path, so that a pressure change in the communicating channel is detected, after the drive power is inputted to the communicating channel and then the opening/closing valve is closed.

It is further characterized in that, in the stack pitch changing device according to claim 1, the operating member comprises suction pad(s) that absorb the work.

It is further characterized in that, in the stack pitch changing device according to claim 1, the operating member comprises clamping member(s) that clamp the work.

It is further characterized in that, in the stack pitch changing device according to claim 1, the base plates are classified into groups, each group comprising a predetermined number of the base plates.

It is further characterized in that, in the stack pitch changing device according to claim 1, each base plate is provided with a pair of the operating members, and each base plate is provided with a pair of the communicating channels that communicate with the variable spacers and the operating members.

It is further characterized in that, in the stack pitch changing device according to claim 1, the operating member(s) support surface(s) of the work extending perpendicularly to a stacking direction.

It is further characterized in that, in the stack pitch changing device according to claim 1, the operating member(s) support surface(s) of the work extending along a stacking direction.

According to the present invention, there is also provided means for holding the work in the stack pitch changing device, which comprises a suction pad for use in a device for changing a pitch of a stack characterized in that airtight, expandable communicating channel(s) is formed between the base plates.

Effect of the Invention

In accordance with the present invention, it is possible to change a stack pitch only, while keeping a stack or works in a stacked form. Therefore, it is possible to efficiently transfer a stack stored in one container in a stacked form with one pitch (a small pitch, for example) to another container in which it is stored in a stacked form with another pitch (a large pitch, for example), while doing pitch changing operation.

The above-described transfer may be accomplished all at once, while keeping a stack or works in a stacked form. Therefore, the transfer operation may be achieved surely, stably and smoothly.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view, partly omitted, showing an essential part of a stack pitch changing device embodying the present invention.

FIG. 2: (A) is an A-B-C-D sectional view in FIG. 1 when the springs are in a compressed form, (B) is an enlarged view of B part in (A), (C) is an A-B-C-D sectional view in FIG. 1 when the springs are in an expanded form, and (D) is an enlarged view of D part in (C).

FIG. 3: (A) is an E-F-G-H-I-J sectional view in FIG. 1 when the variable spacer is set for small pitch application, (B) is an enlarged view of B part in (A), (C) is an E-F-G-H-I-J sectional view in FIG. 1 when the variable spacer is set for large pitch application, and (D) is an enlarged view of D part in (C).

FIG. 4 is a plan view of FIG. 3(A).

FIG. 5: (A) is a front view showing a base plate and accessories thereof, and (B) is a B-B sectional view in (A) in an enlarged scale.

FIG. 6: (A) is a front view of a suction pad in FIG. 1, (B) is a bottom view of (A), and (C) is a right side view of (A).

FIG. 7: (A) is a front view of a variable spacer, (B) is a B-B sectional view in (A), and (C) is an enlarged view of C part in (B).

FIG. 8: (A) is a view showing position of communicating channels, (B) is a view showing different position of communicating channels, and (C) is a view showing still different position of communicating channels.

FIG. 9 is a plane view showing position of communicating channels.

FIG. 10 is a front view, partly in section, showing a release spring used in the stack pitch changing device of FIG. 1.

FIG. 11: (A) is a right side view of FIG. 1, (B) is a view showing a combination of the release springs of (A) in each block, and (C) is a graph diagrammatically showing restoring forces of the release springs.

FIG. 12 shows a valve that opens and closes the communicating channel in FIG. 1 and an orifice, wherein (A) shows the same when the valve is in an opened state, and (B) shows the same when the valve is in a closed state.

FIG. 13 is a view showing a flow of operation of the stack pitch changing device according to the present invention.

FIG. 14: (A) is a front view of another operating member, (B) is a bottom view of (A) and (C) is a right side view of (A).

EMBODIMENTS FOR PRACTICING THE INVENTION

Next, a device for changing a pitch of a stack according to the present invention will be described in more detail in reference to the drawings that illustrate the embodiments thereof. For the sake of convenience, parts serving the same function are indicated by the same reference numerals and explanation thereof will be omitted.

As shown in FIG. 1 to FIG. 4, the stack pitch changing device E according to the present invention comprises a movable suction unit 1 operating as a movable holder unit and a drive unit for driving the movable suction unit 1. The movable suction unit 1 comprises a plurality of base plates 3 juxtaposed in a stacked form with a predetermined pitch. Each of a group of the base plates 3 that constitute the movable suction unit 1 is made from a rectangular tabular piece having the same construction. Each base plate 3 has a pair of holes 5 at the center thereof, as shown in detail in FIG. 5. The hole 5 has a bottom and is formed as a rectangular hole 5 a larger than a radius of a variable spacer 17 to define a clearance for a large pitch section 20, when the variable spacer 17 is set to a small pitch section 19. At a middle of an outer side of the rectangular hole 5 a is formed an outwardly recessed, semi-circular cutout 5 b to allow rotation of a drive shaft 31. In the illustrated embodiment, the cutout 5 b of the hole 5 has a bottom, which is a preferable embodiment, because it will prevent excessive entry of a large pitch section 20 into the cutout 5 b, when a small pitch should be applied. At the left and right ends of each base plate 3 are formed a pair of upper and lower circular recesses 7. As shown in detail in FIG. 2(B), (D), a bellows-like release spring 9 comprising a layer of four dish springs 90 is fitted in the recess 7. A circular hole 8 is formed between the recesses 7, and a slide guide 11 formed by a round bar is inserted into the circular hole 8. At the end portion of each base plate 3 is formed a pair of hole sets, each set comprising three circular through holes 13 a, 13 b, 13 c, to which elastic packings 15 a, 15 b, 15 c (referred to as “elastic packings 15” as a general term for them) made from elastic material capable of expansion and contraction are fitted respectively. As shown in detail in FIG. 2(A) to (D), to each through holes 13 a, 13 b, 13 c is connected a joint 40 a, 40 b, 40 c (referred to as “joints 40” as a general term for them), having an open hole, to allow entry and discharge of air.

A variable spacer 17 is located at a center of the cutout 5 b of each base plate 3. The variable spacer 17 is inserted into a rotatable drive shaft 31 made of a square bar. The variable spacer 17 is made of a disk, as shown in FIG. 7, and provided at a center with a square center hole 18 for insertion of the drive shaft 31. The variable spacer 17 has different circumferential surface parts having different thickness, i.e., a small pitch part 19 of a smaller thickness d₁ and a large pitch part 20 of a larger thickness d₂. The small pitch part 19 and the large pitch part 20 are connected to each other via an inclined part 21.

The variable spacer 17 is located between the adjacent base plates 3 and inserted into the rotatable drive shaft 31 made of a square bar. By this, the variable spacer 17 is rotated along with rotation of the drive shaft 31 to change the operating surface of the small pitch part 19 or the large pitch part 20 to be in contact with the adjacent base plates 3. It will also be moved horizontally along with horizontal movement of the base plates 3.

At a position further beneath the through holes 13 a, 13 b, 13 c (referred to as “through holes 13” as a general term for them), a distribution plate 23 is fitted interchangeably with the base plate 3. Suction pads 25 working as operating members are interchangeably attached to the lower end of the distribution plate 23. The distribution plate 23 has an internal pathway 26, and the pathway 26 communicates with a small pathway 27 provided in the suction pad 25.

An expandable communicating channel 28 comprises the elastic packings 15 fitted in the through holes 13 of the base plate 3, the pathway 26 formed in the distribution plate 23 and the small pathway 27 formed in the suction pad 25. The communicating channel 28 communicates with a suction port 29 formed in the suction pad 25. The suction port 29 is formed preferably at a part of the suction pad 25 corresponding to a part of the work 51 which would often be broken or damaged from the experience. In this embodiment, among the through holes 13, the first through hole 13 a will correspond to 1^(st) to 10^(th) works 51, the second through hole 13 b will correspond to 11^(th) to 20^(th) works 51 and the third through hole 13 c will correspond to 21^(st) to 30^(th) works 51, which will respectively form a first communicating channel 28 a (FIG. 8(A)), a second communicating channel 28 b (FIG. 8(B)) and a third communicating channel 28 c (FIG. 8(C)), as shown by hatched lines in FIG. 8. A reference numeral 27 a denotes a narrowed part formed at a boundary between the small pathway 27 and the suction port 29 (shown in FIG. 5 and FIG. 6). An opening of the narrowed part 27 a has an opening, which is larger than an opening of an orifice 46 to be described later, when compared in cross-section.

In FIG. 2 and FIG. 9, a reference numeral 32 denotes a guide rod for insertion of the respective release springs 9, 33 a stopper mounted on a pedestal 34 for contact with the open end of the base plates 3, 35 a slide bush disposed at an open end of the push plate 41, and 36 a movable cylinder for determining a pitch between the works 51. A reference numeral 40 a denotes a first joint for 1S^(t) to 10 ^(th) works 51, 40 b a second joint for 11^(th) to 20^(th) works 51, and 40 c a third joint for 21^(st) to 30^(th) works 51. The joints 40 a, 40 b, 40 c are respectively connected to the first communicating channel 28 a for 1^(st) to 10^(th) works 51, the second communicating channel 28 b for 11^(th) to 20^(th) works 51 and the third communicating channel 28 c for 21^(st) to 30^(th) works 51. Each joint 40 a, 40 b, 40 c is connected to a vacuum source, not shown, and a drive power from the vacuum source is supplied to the respective communicating channels 28 a, 28 b, 28 c. In FIG. 3 and FIG. 4, a reference numeral 37 denotes a rotation actuator for driving the drive shaft 31, 38 a coupling for transmitting the drive power from the rotation actuator 37 to the drive shaft 31, 39 bearings mounted at opposite ends of the drive shaft 31, 41 a movable push plate mounted at the open end of the base plates 3, and 43 a stationary reference plate mounted at a base end of the base plates 3. In these drawings, an arrow A indicates a direction of a push stroke of the pitch determining cylinder 36 and an arrow B indicates a direction of a restoring force of the release spring 9.

Now, the release spring 9 will be described in detail. Each spring 90 that constitutes the release spring 9 has a hole at a central part 9 p and inclined peripheral parts 9 q, as shown in FIG. 10, which is fitted to the base plate 3 as a four-ply unit, as described before. As shown in FIG. 11(A) and FIG. 11(B), a release spring 9 comprises two pairs of springs 9 o, each comprising a pair of springs superimposed with each other with their central parts 9 p opposed to each other, each pair being superimposed with each other with their bottom portions 9 r opposed to each other. Regarding the spring force for restoring the contracted base plate 3, a restoring spring force of the spring at a side of the reference plate 43 is determined greater than a restoring spring force of the spring at a side of the push plate 41. In the embodiment of FIG. 11, the release springs 9 have different spring forces for three blocks 10A, 10B, 10C. With regard to relationship of the spring forces among the respective release springs 9 in the first block 10A to the third block 10C, the spring force becomes greater in a predetermined ratio for every unit number (that is five, in the illustrated example) of the works 51, so that, as shown in FIG. 11(C), the restoring forces of the release springs 9 are increased in stages. More specifically, the spring force P₁ of the release spring 9A in the first block 10A is larger than the spring force P₂ of the release spring 9B or 9C in the second block 10B, which is larger than the spring force P₃ of the release spring 9D to 9J in the third block 10C. Further, in the release spring 9A in the first block 10A, the unit spring 9 a has a great strength, the unit spring 9 b has an intermediate strength, and the unit spring 9 c, 9 d have a small strength. In the release spring 9B in the second block 10B, the unit spring 9 e has a great strength, and the unit spring 9 f, 9 g, 9 h have a small strength. This is also applicable to the springs in the release spring 9C. The four unit springs in the release springs 9D to 9J in the third block 10C have the same spring force of a small strength. Incidentally, the number of the base plates 3 shown in FIG. 11(A) is not exactly matched with the number of the base plates 3 shown in FIG. 2 to FIG. 4, because they are conveniently shown for the sake of explanation. In FIG. 11(C), an X-axis indicates position of the release spring 9 when the small pitch is applicable, whereas a Y-axis indicates the spring force of the release spring 9 when the small pitch is applicable.

As shown in FIG. 12, the communicating channel 28 is formed in a vacuum supply chamber 44 of a chamber block 42, where a valve 45 for opening and closing the vacuum supply chamber 44 is mounted. A reference numeral 46 denotes an orifice formed in the opening/closing valve 45. A reference numeral 47 denotes a vacuum pressure detection path formed in the chamber block 42. One end portion of the vacuum pressure detection path 47 communicates with the orifice 46, through a small path 47 a communicating with the vacuum pressure supply chamber 44, and the other end is connected to a vacuum pressure detection sensor 48 (shown in FIG. 11) through another joint 40 d. A reference numeral 49 denotes a cylinder for driving the opening/closing valve 45. A work condition detection unit comprises the opening/closing valve 45, the orifice 46, the small path 47 a, the vacuum pressure detection path 47 and the vacuum pressure detection sensor 48.

In the meantime, a ratio of opening of the orifice 46 in comparison with the suction pad 25 is important. More specifically, an opening area of the orifice 46 should be smaller than an opening area of the narrowed part 27 a formed in the suction pad 25. In this embodiment, the opening area of the orifice 46 is about one-sixth of the narrowed part 27 a in a ratio of cross section.

Next, based on FIG. 13, the operation of transferring a stack stored and stacked in a small container 52 with one pitch (a small pitch, for example) to a large container 53 for storing and stacking the stack with another pitch (a large pitch, for example) will be described. The size of the small pitch section 19 of the variable spacer 17 should be set in advance to conform with the pitch between the works 51 to be stored in the small container 52, whereas the size of the large pitch section 20 of the variable spacer 17 should be set in advance to conform with the pitch between the works 51 to be stored in the large container 53.

At first, the pitch-determining cylinder 36 is extended and the base plates 3 are pushed by the push plate 41 toward the reference plate 43, so that a pitch between the base plates 3 is set to conform with the pitch of the works 51 (the small pitch shown in FIG. 3(A),(B)) stored in a stacked form in the small container 52 (FIG. 13(A)).

Then, the movable suction unit 1 is moved vertically in a direction of an arrow C shown in FIG. 13(A) to be inserted into the small container 52 with the small pitch. The respective base plates 3 of the movable suction unit 1 will operate such that the respective suction pads 25 are inserted into a space between the respective works 51 so that the respective suction pads 25 absorb the respective works 51. The respective suction pads 25 absorb the surface of the work extending perpendicularly to the stacking direction, that is a front surface 51 a (shown by a dashed line in FIG. 1) or a back surface of the work 51.

This absorption will be achieved by a pressure reduction in the communicating channel 28 by the vacuum source, not shown, so that the respective works 51 are adhered to the suction ports 29 of the respective suction pads 25. At this time, the pressure reduction in the communicating channel 28 will be applied simultaneously to the first communicating channel 28 a, the second communicating channel 28 b and the third communicating channel 28 c. By this, the stack 50 stored in a stacked form in the small container 52 has been set to the movable suction unit 1.

Then, the movable suction unit 1 is moved vertically in a direction opposite to an arrow C so that the stack 50 is removed from the small container 52, and the movable suction unit 1 is moved horizontally to the large container 53 in which the works 51 should be stored with a different pitch.

During the movement toward the large container 53, the pitch between the base plates 3 is changed to the large pitch shown in FIG. 3(C),(D). This process is shown in FIG. 13(B),(C).

At first, each base plate 3 is pushed by the restoring force of the installed release spring 9 to be moved toward the push plate 41, so that the movable suction unit 1 is extended from the contracted state to reach the open end. This state is shown in FIG. 13(B). At this time, the movable suction unit 1 may extend smoothly, because the release spring 9 is designed such that a restoring force of the spring at the side of the reference plate 43 is set greater than a restoring force of the spring at the side of the push plate 41.

Then, the rotation actuator 37 is rotated. This will rotate each variable spacer 17 inserted into the rotation actuator 37, so that the large pitch section 20 becomes into contact with the base plates 3. This state is shown in FIG. 13(C).

Then, the pitch determining cylinder 36 is extended so that the operating surface of each variable spacer 17 being in contact with each base plate 3 is fixed at the large pitch d₂ shown in FIG. 7(B). This state is shown in FIG. 13(D).

In this state, the movable suction unit 1 is moved vertically in a direction of an arrow D shown in FIG. 13(D), and then the suction operation of each suction pad 25 is terminated so that the works 51 are thrown into the large container 53 with the large pitch (FIG. 13(D)), while keeping the stacked form. Also at the time of terminating the suction operation during the transfer, the pressure reduction in the communicating channel 28 will be terminated simultaneously to the first communicating channel 28 a, the second communicating channel 28 b and the third communicating channel 28 c.

Then, the movable suction unit 1 is moved vertically in a direction opposite to the arrow D shown in FIG. 13(D), and the pitch determining cylinder 36 is contracted. Each base plate 3 is pushed toward the push plate 41 by the restoring force of the installed release spring 9, so that the movable suction unit 1 extends to reach the open end. By this, each variable spacer 17 that has been in contact with the base plates 3 is detached therefrom. This state is shown in FIG. 13(E). At this time, the movable suction unit 1 may extend smoothly, because the release spring 9 is designed such that a restoring force of the spring at the side of the reference plate 43 is set greater than a restoring force of the spring at the side of the push plate 41.

Then, the rotation actuator 37 is rotated. This will rotate each variable spacer 17 inserted into the rotation actuator 37, so that the small pitch section 19 becomes into contact with the base plates 3. This state is shown in FIG. 13(F).

Then, the pitch determining cylinder 36 is extended so that the operating surface of each variable spacer 17 being in contact with each base plate 3 is fixed to define the small pitch d₁ shown in FIG. 7(B). This means that it is returned to the first state shown in FIG. 13(A).

When a large number of the works are stored in the container, a series of the above-described steps is repeated until the transfer operation is completed.

Transfer of the works from the large-pitch container 53 to the small-pitch container 52 may also be executed. This transfer will start from the state of FIG. 13(D) and return to the state of FIG. 13(D), via the above-described steps in the order of FIG. 13(E), FIG. 13(F), FIG. 13(A), FIG. 13(B) and FIG. 13(C).

With regard to the absorption of each work 51 by each suction pad 25, the elastic packing 15 is fitted to the through hole 13 of each base plate 3 to form the communicating channel 28, through which this operation is achieved by each suction pad 25. This will guarantee the air-tightness of the communicating channel 28, which makes it possible to transfer the stack 50, while maintaining the stacked form of the works 51. Accordingly, it is possible to smoothly, speedily and effectively transfer the stack 50 with a pitch change.

This will be described in more detail. Each communicating channel 28 opens at the suction port 29 of each suction pad 25 through the elastic packing 15, and position of the elastic packing 15 is moved horizontally along with movement of the base plate 3. Although one elastic packing 15 is very small in amplitude of expansion/contraction, there will be a great difference between an amount of movement of the elastic packing 15 a adjacent to the reference plate 43 and an amount of movement of the elastic packing 15 n adjacent to the push plate 41 at the open end, assuming that each elastic packing 15 is not moved. For example, when each elastic packing 15 is expandable/contractable in an amplitude of 0.8 mm, assuming that each elastic packing 15 is not moved, an amount of movement of the elastic packing 15 a is 0.8 mm, whereas an amount of movement of the elastic packing 15 n is much larger, which is calculated by “0.8 mm×(30-1)=23.2 mm”, in an example of n=30. Consequently, if each elastic packing 15 should not be movable, the communicating channel 28 including the elastic packing 15 positioned remote from the reference plate 43 could not be vacuumed, which makes it difficult to absorb the work 51. However, in accordance with the present invention, since each elastic packing 15 is movable horizontally along with movement of the base plate 3, such a degree (0.8 mm) of expansion/contraction will be absorbed by elasticity of the elastic packing 15. Accordingly, all of the elastic packing 15 a (shown in FIG. 2(A),(C)) to the elastic packing 15 n (shown in FIG. 2(A),(C)) have a constant expansion/contraction amplitude (0.8 mm in this embodiment), and all of the elastic packings 15 at different position will be moved over a constant amount, which will always assure the air-tightness of the communicating channel 28. In addition, the assurance of air-tightness of the communicating channel 28 will not be affected by the number of the elastic packings 15.

In accordance with the above-described embodiment, a pair of the suction pads 25 is mounted to each base plate 3 so that, when absorbing and holding the works 51, the release springs 9 are arranged in a left-right symmetry, as well as in an up-down symmetry with respect to the slide guide 11, and the variable spacers 17 are arranged in a left-right symmetry, which assures well-balanced arrangement and provides an effect of making the device mechanically more stable.

In the above-identified embodiment, it is possible to accomplish transfer of 30 works 51 all at once, while keeping a stack or works in a stacked form. This makes it possible to achieve the transfer operation surely and stably.

In the above-described embodiment, a plurality of works 51 are handled every group under the control of three communicating channels 28, so that, even if there should be any defects in the base plates 3 belonging to one group, that corresponds the first communicating channel 28 a, for example, the second communicating channel 28 b and the third communicating channel 28 c belonging to other groups will continue in operation. This will also contribute to optimization of transfer operation. It is also possible to change the contents of transfer operation for every group.

In the above-described embodiment, a load to the release spring 9 at the reference plate 43 is always greater than a load to the release spring 9 at the push plate 41, so that it is designed such that the release spring 9 at the reference plate 43 has a restoring force greater than a restoring force of the release spring 9 at the push plate 41. Accordingly, well-balanced depression is applied to the respective base plates 3 as a whole, when changing a pitch between the base plates 3, that is when the base plates 3 are depressed by the release spring 9 from the position of FIG. 13(A) to the position of FIG. 13(B) and from the position of FIG. 13(D) to the position of FIG. 13(E), which assures smooth return of the base plates 3 to the post-transfer position. With regard to this point, if the release springs should have a constant strength, the release springs might not work.

In case of the embodiment of FIG. 11, the release springs 9A in the first block 10A at a side of the reference plate 43 has a depressing force P₁ of 190 kg, the release springs 9B, 9C in the second block 10B has a depressing force P₂ of 170 kg, and the release springs 9D-9J in the third block 10C has a depressing force P₃ of 150 kg. Because the release springs 9 having such different restoring forces are mounted to the base plates 3, the release springs 9 of the base plates 3 will be expanded and restored at the same time, which assures uniform extension of a group of the base plates 3 that have been contracted to each other in a block form, thereby making it possible to proceed to the next step.

In the meantime, if there should be any defects such as crack and damage in the work 51 during the step of absorbing the work 51 by the suction pad 25, air would enter through the cracked or damaged area. Even in this case, when there is the work condition detection unit shown in FIG. 12, the vacuum pressure detection sensor 48 detects an increase of an air pressure in the communicating channel 28 resulting from entry of air through the cracked or damaged area, thereby outputting a defect signal. This defect signal may be displayed digitally in a display not shown, or may not be displayed. When the work 51 is normal, the suction pad 25 will absorb and hold the work 51 without being affected by the air flowing through the orifice 46, because its amount is extremely small.

When there is some defect such as crack and damage in the work 51, a vacuum pressure in the communicating channel 28 is changed, and this change may be detected before the transfer. This will further improve the assurance of the transfer.

The device for changing a pitch of a stack according to the present invention is not limited to the above-described embodiments. By way of example, regarding the operating member that holds each work 51, a clamping member 65 may be used to clamp the work 51, as shown in FIG. 14, rather than using the absorption by the suction pad 25, which will also be an embodiment of the present invention. In case of FIG. 14, the clamping member 65 comprises a pair of opening/closing movable arms 65 a, 65 b connected to each other by a spring 65 c, and there is a pathway 66 communicated with the communicating channel 28 at a base end portion. The spring 65 c is always biased toward the opened condition. When an interior of the communicating channel 28 is vacuumed by the vacuum source to a degree greater than the biasing force of the spring 65 c, the movable arms 65 a, 65 b are “closed” to each other, so that the movable arms 65 a, 65 b hold the sides 51 b of the work 51 therebetween, as shown by dashed lines in FIG. 14(A) and FIG. 14(B).

The operating member such as the suction pad 25 and the clamping member 65 may not necessarily require one pair, which may comprise only one or three or more. Which side of the work to be held by the operating member is optional and, for example, the work 51 may be hold from the sides of the work extending along the stacking direction, that is the opposite sides 51 b of the work, as shown in FIG. 14(A).

The number of communicating channel 28 is optional, which may suitably be changed depending upon the number of works to be applied.

When a plurality of communicating channels 28 is mounted, they may be operated in a sequential manner. This will be advantageous, when the vacuum source has a small volume, for example.

Although the elastic packing 15 is shown as a bellow-like one in the illustrated embodiment, this is not limited thereto and may comprise rubber packing, )-ring, etc. having elasticity. In any case, it is movable along with movement of the base plate 3.

The pitch sections formed on the circumferential surface of the variable spacer 17 may comprise three sections consisting of large, middle and small sections or more than three sections. When three pitch sections are be formed, they may be formed at 120 degrees interval. In such a way, when a plural pitch sections are to be formed, the pitch sections are formed at suitably changed position.

The pitch sections may not necessarily be allotted equally. For example, when there are large and small pitch sections to be formed, it may be designed such that the large pitch section is formed at 60%, while the small pitch section 40%. When there are large, middle and small pitch sections to be formed, it may be designed such that the large pitch section is formed at 40%, while the middle pitch section 35% and the small pitch section 25%.

The time of changing the pitch between the base plates 3 is optional. Although this may be done on the way of transfer of the works 51 as in the illustrated embodiment, the pitch between the base plates 3 may be changed while the movable holder unit is being moved vertically to the small container 52 prior to the transfer, or while the movable holder unit is being moved vertically to the large container 53 after the transfer.

The direction of movement of the movable holder unit is optional. The movable holder unit is moved horizontally in the illustrated embodiment, but it may be moved vertically or obliquely.

The direction of stack of the base plates 3 constituting the movable holder unit is optional.

The shape of the base plate 3 is optional.

Although the respective parts may be made from any material, the base plate 3, the variable spacer 17 and the release spring 9 are preferably made from material having high durability, such as metallic material. The elastic packing 15 are preferably made from material having high elasticity, such as plastic material and rubber material. The suction pad 25 is preferably made from suitable plastic material, for example, from the standpoints of lightweight, workability, chemical-resistance and having hardness smaller than the work. The distribution plate 23 is preferably made from suitable plastic material or lightweight metallic material, for example, from the standpoints of lightweight and workability.

The drive power is optional, which may be obtained from a pressurization source, for example, rather than from the vacuum source.

With regard to the spring force of the release spring 9, it is preferred that the release spring 9 mounted to the base plate 3 at the side of the reference plate 43 has the greatest restoring force, which is gradually and linearly reduced toward the release spring 9 of the side of the push plate 41. However, as described above, it has been demonstrated that another embodiment is almost preferable wherein it is decreased stepwise toward the side of the push plate 41, for every predetermined number (a unit number) of the base plates 3.

The number of the release springs 9 and the number of the recesses 7 are also optional, which may be changed depending upon the pitch size to be determined.

The device for changing a pitch of a stack according to the present invention is not limited to the above-described embodiment. By way of example, with regard to the opening/closing of the opening/closing valve 45, the opening/closing valve 45 is always opened, which is closed during the inspection, in the above-described embodiment, but this is not limitative.

INDUSTRIAL APPLICABILITY

The device for changing a pitch of a stack according to the present invention is applicable to a device for changing a pitch between the works, when a plurality of thin works are juxtaposed in a stacked form with a predetermined pitch, for use, for example, in transfer of solar panels.

LEGENDS

1 movable suction unit

3 base plate

5 hole

5 a rectangular hole

5 b cutout

7 recess

8 circular hole

9 release spring

90 spring

9 p central part

9 q peripheral part

9 r bottom part

10A first block

10B second block

10C third block

11 slide guide

13 through hole

13 a first through hole

13 b second through hole

13 c third through hole

15 elastic packing

15 a first elastic packing

15 b second elastic packing

15 c third elastic packing

17 variable spacer

18 central hole

19 small pitch section

20 large pitch section

21 inclined part

23 distribution plate

25 suction pad

26 pathway

27 small pathway

27 a narrowed part

28 communicating channel

28 a first communicating channel

28 b second communicating channel

28 c third communicating channel

29 suction port

31 drive shaft

32 guide rod

33 stopper

34 pedestal

35 slide bush

36 pitch-determining cylinder

37 rotation actuator

38 coupling

39 bearing

40 a first joint

40 b second joint

40 c third joint

40 d another joint

41 push plate

42 chamber block

43 reference plate

44 vacuum supply chamber

45 opening/closing valve

46 orifice

47 vacuum pressure detection path

48 vacuum pressure detection sensor

49 cylinder

50 stack

51 work

52 small container

53 large container

65 clamping member

65 a movable arm

65 b movable arm

65 c spring

66 pathway 

1. A device for changing a pitch of a plurality of thin works juxtaposed in a stacked form with a predetermined pitch between adjacent ones, characterized in that; it comprises a movable holder unit and a drive unit for driving the movable holder unit; the movable holder unit comprises a plurality of base plates juxtaposed in a stacked form with a predetermined pitch, each of said base plates includes operating member(s) that support the work, the operating member(s) being driven by drive power supplied from communicating channel(s) to hold the work individually; each of said base plates includes rotatable variable spacer(s) interlocking with a drive shaft of the drive unit, and the pitch between the base plates becomes variable by rotation of the variable spacer(s); and when the work is held by each of said base plate, the airtight, expandable communicating channel(s) is formed between the base plates in communication with the operating member.
 2. The stack pitch changing device according to claim 1, wherein the communicating channel is formed by expandable elastic packings mounted in series between through holes of the adjacent base plates.
 3. The stack pitch changing device according to claim 2, wherein each of said elastic packing is moved along with each of said base plate.
 4. The stack pitch changing device according to claim 1, wherein each of said variable spacer is moved along with each of said base plate.
 5. It is further characterized in that, in the stack pitch changing device according to claim 1, wherein each of said base plate is provided with spring(s) for releasing the fixed pitch between the base plates.
 6. The stack pitch changing device according to claim 2, wherein the elastic packing is formed like bellows.
 7. The stack pitch changing device according to claim 1, wherein the variable spacer has different parts having different thickness formed on its circumferential surface, and the pitch between the base plates may be changed by rotating the variable spacer so that the base plate becomes in contact with another part of different thickness.
 8. The stack pitch changing device according to claim 5, wherein the spring at a side of a stationary base plate has a spring force for restoring the contracted base plate, which is greater than a spring force of the spring at a side of a movable base plate.
 9. The stack pitch changing device according to claim 8, wherein the spring forces are made smaller stepwise toward the movable base plate for every predetermined number of the base plate.
 10. The stack pitch changing device according to claim 8, wherein the spring forces are made smaller linearly toward the movable base plate.
 11. The stack pitch changing device according to claim 5, wherein the spring comprises a single spring.
 12. The stack pitch changing device according to claim 5, wherein the springs comprise a stack of plural springs.
 13. The stack pitch changing device according to claim 1, wherein there is provided a detection unit for detecting the work condition such as crack or damage when absorbing the work.
 14. The stack pitch changing device according to claim 13, wherein the detection unit comprises an opening/closing valve mounted at an entrance of the communicating channel for opening and closing the communicating channel, an orifice mounted to the opening/closing valve in communication with a vacuum pressure detection path, and a sensor connected to the vacuum pressure detection path, so that a pressure change in the communicating channel is detected, after the drive power is inputted to the communicating channel and then the opening/closing valve is closed.
 15. The stack pitch changing device according to claim 1, wherein the operating member comprises suction pad(s) that absorb the work.
 16. The stack pitch changing device according to claim 1, wherein the operating member comprises clamping member(s) that clamp the work.
 17. The stack pitch changing device according to claim 1, wherein the base plates are classified into groups, each group comprising a predetermined number of the base plates.
 18. The stack pitch changing device according to claim 1, wherein each of said base plates is provided with a pair of the operating members, and each of said base plates is provided with a pair of the communicating channels that communicate with the variable spacers and the operating members.
 19. The stack pitch changing device according to claim 1, wherein the operating member(s) support surface(s) of the work extending perpendicularly to a stacking direction.
 20. The stack pitch changing device according to claim 1, wherein the operating member(s) support surface(s) of the work extending along a stacking direction.
 21. A suction pad for use in a device for changing a pitch of a stack as means for holding a work, characterized in that airtight, expandable communicating channel(s) is formed between the base plates. 